Copper has been mechanically alloyed with the bcc structure type elements Nb and Mo in order to obtain a material with high strength, good ductility and good electrical conductivity. In the case of alloying Cu with Nb a solid solution is formed during milling, whereas in the case of alloying Cu and Mo a fine distribution of Mo particles within the copper matrix is observed. The different behaviour of these two alloys is related to the large difference of the elastic constants of the bcc elements. Niobium precipitates from the solid solution and molybdenum particles coarsen during a subsequent heat treatment. (C) 2004 Kluwer Academic Publishers.